1. Field of the Invention
The present invention is generally directed to a system for temporarily shoring up an excavation site. More particularly the invention is directed to a reinforcing assembly for a corner connection used in a reinforcing arrangement that supports sheet piling in an excavation site.
2. Description of the Prior Art
In a typical excavation site, workers are exposed to numerous hazards. The most common hazard is having the walls of the excavation site cave in on the workers, thus causing serious injury. Often due to soil conditions and wetness, the sides of a construction site will simply collapse. Water is a particularly dangerous hazard because it is so heavy and can destroy shoring, which has not been properly reinforced. Realizing this problem the government, at both the federal and state level, has set up specific requirements for all excavation sites to avoid the problem of cave-ins. For example the United States Department of Labor and, more specifically, the Occupational Safety and Health Administration (OSHA) requires that excavation sites be prepared with some type of shoring. Additionally many companies are now aware of the problems involved in a typical excavation site and have developed internal policies requiring shoring for any excavations they contract to have completed.
A good example of a typical excavation project is found in replacing underground storage tanks for a gasoline station. Typically, in such an operation, sheet piling is pounded into the ground in a generally rectangular configuration around the work site. The piling has to be driven extremely deeply into the ground and arranged to provide sufficient support against potential cave-ins. Typically the sheet piling has to be driven so deep that half its total height remains underground after the excavation has been completed. Use of such large amounts of material is quite expensive. After the sheet piling has been installed, the workmen then remove the dirt and fill material from within the rectangular shoring. During the work of removing the old storage tanks and replacing them with new storage tanks the shoring provides protection to the workmen against potential cave-ins. Once the storage tank replacement operation has been completed the shoring can either be completely removed or simply cut down We to a safe distance below ground and then left in place. Such a method of shoring an excavation site is extremely expensive.
Various solutions have been proposed in an attempt to cut down on the costs of shoring an excavation site. For example U.S. Pat. No. 5,154,541 discloses a modular earth support system. Specifically, the patent teaches using panels placed around an excavation site and interlocked with one another to form a generally rectangular shoring configuration. Once the panels are in place, reinforcing beams are placed behind the panels to ensure the weight and force of the dirt behind the panels does not cause the panels to fail. The main drawback of using such a system is that standard I-beams cannot be used. Rather, special beams that are cut exactly to size and additionally have a customized end configuration must be used. Such beams are particularly expensive; especially considering a large number of beams of varying sizes would have to be kept available for differently sized excavation sites.
Another proposed solution to reducing the high cost of shoring excavation sites is found in U.S. Pat. No. 4,685,837. This patent proposes using panels as shoring members in an excavation site and uses laterally extending braces to reinforce the panels. The braces are connected to one another by a bracket. Alternatively, the braces maybe connected to each other by means of a connection in which one brace has a pair of tabs welded thereto with each tab having an aperture formed therein. The apertures align with a hole in a second brace and a pin is placed though the apertures to complete the connection. In either case there is no provision to adjust the length of the braces and connectors and they must be custom made for each different sized excavation site.
Numerous other proposed solutions are available including using wooden shoring which is a custom made to a particular excavation site. Such shoring is used only at the designated site and then disposed of. As a result this approach is prohibitively expensive. Also wooden shoring is not as durable as its metal counterparts. Often water along with regular wear and tear at the construction site can destroy the shoring during the construction job.
Perhaps the best solution proposed so far is set forth in U.S. Pat. No. 6,416,259 which is incorporated herein by reference. In that patent a corner connection for temporary shoring is shown as being used in an excavation site. Specifically, the corner connection is used to secure I-beams together at corners within the excavation site. Typically, four I-beams are connected together to form a rectangular frame that is suspended within the excavation for bracing the shoring walls thereof. The corner connection itself comprises mating socket or connecting members that are placed over the ends of I-beams to be fastened together. Some portions of this prior patent are summarized below in the discussion of FIGS. 4 and 5 labeled “Prior Art”.
Turning now to FIG. 4, there is illustrated a close-up view of a corner connection 11 located at the ends of two I-beams 20, 21, including two meeting connectors 29, 30. Each connector 29, 30 has a similar overall shape. However, one type of connector 29 has a single tab 32 while the other type of connector 30 has a double tab 34, 36. A single tab type connector 29 shown in FIG. 4 includes a box-like main body portion 40 having an opening 45 therein for receiving an I-beam 21. The box-like main body portion 40 comprises five major panels to form the open box shape. Opposing top 50 and bottom 51 panels are connected with opposing side panels 55, 56 to form the square or rectangular opening 45 designed to receive the I-beam 21. An end panel 57 also preferably square or rectangular in shape closes off one end of the box type main body 40. These five pieces 50, 51, 55, 56, 57 are all made of heavy steel and are welded together. The end panel 57 and one of the side panels 56 have the single tab 32 welded thereto. The tab 32 is a flat plate like member that extends laterally from the box-like main body portion 40 of the connector 29 and has an aperture 60 formed therein. The tab 32 is made of a similar material as the panels of the box-like main body 40. The tab 32 is preferably welded to the side 56 and end 57 panels.
A double tab type connector 30 shown in FIG. 4 includes a box-like main body portion 70 having an opening 75 therein for receiving an I-beam 20. The box-like main body portion 70 comprises five major panels to form the open box shape. Opposing top 80 and bottom 81 panels are connected with opposing side panels 85, 86 to form the square or rectangular opening 75 designed to receive the I-beam 20. An end panel 87 also preferably square or rectangular in shape closes off one end of the box type main body 70. These five pieces 80, 81, 85, 86, 87 are all made of heavy steel and are welded together. The end panel 87 and one of the side panels 86 have top and bottom tabs 34, 36 welded thereto. The tabs 34, 36 are flat members which extend laterally from the box-like main body portion 70 of the connector 30 and each have an aperture 90, 91 formed therein. The tabs 34, 36 are made of a similar material as the panels of the box-like main body 70. The tabs 34, 36 are preferably welded to the side 86 and end 87 panels. While other methods may be used to attach the tabs 34, 36 it is important that the tabs 34, 36 be able to withstand the tremendous hydraulic pressures which may be transmitted by sheet piling 219 (seen in FIG. 1) as it starts to buckle.
As can clearly be seen in FIG. 4, connectors 29, 30 may easily be joined together by placing the tab 32 of the single tab connector 29 within the two tabs 34, 36 of the double tab connector 30. Ideally, the single tab aperture 60 aligns with the apertures 90, 91 formed in each of the two tabs 34, 36 of the double tab connector 30. A securing bolt or pin 100 is placed through the aligned apertures 60, 90, 91 in order to pivotably secure the connectors 29, 30 together.
Turning now to FIG. 5, there is shown a second preferred embodiment of the invention. Specifically, the box like connectors 29, 30 of the first embodiment illustrated in FIG. 4 now are shown with modifications to support an added reinforcing member. Since the connectors 29′, 30′ shown in FIG. 5 are based on the connectors 29, 30 shown in FIG. 4 only a discussion of the modifications will be provided here.
Essentially each box type connector 29′, 30′ has a box-like main body 40′, 70′ that has been lengthened along with its corresponding panels 50′, 51′, 55′, 56′, 80′, 81′, 85′, 86′ to provide room to support a pair of extra tabs 101, 102, 103, 104 each tab has an aperture (only two shown) 106, 108 formed therein. A reinforcing bar 120 having a tab 130, 131 located at each end is provided to reinforce the two box type connectors 29′, 30′. The tabs 130, 131 located at the end of reinforcing bar 120 each have an aperture (not shown) located therein which will cooperate and align with the apertures 106, 108, formed in the extra tabs 101, 102, 103, 104 of each box type connector 29′, 30′. A pin 100 may then be placed in the respective apertures once they are in proper alignment to hold the reinforcing bar 120 in place.
However even with this reinforcing bar 120 in place the maximum permissible load may be insufficient and the expense of using heavier materials is always a factor.
Based on the above, therefore there exists a need in the prior art of excavation shoring to provide a system wherein shoring can be provided at an excavation site in an inexpensive and reusable manner that does not suffer the disadvantages of the prior art discussed above. More specifically there exists in the art a need to provide a connector for interconnecting various beams used to reinforce shoring in a manner which may allow much greater loading than previously has been available but still uses the same parts as used in previous shoring systems.